For people with chronic back pain, everyday movements like bending down to tie their shoes or picking up a grocery bag can trigger painful flare-ups. Now, scientists have made a surprising discovery: These episodes may activate a brain network that's associated with our sense of self.In a new study, the researchers found that movement-induced chronic back pain was tied to increased activity in the brain's default mode network, a group of connected brain regions that lights up during self-reflection and mind wandering. This finding was unexpected because the network typically becomes less active during acute pain, such as transient pain triggered from touching a hot stove or banging your knee...